Q.1

A compressor at high altitudes will require __________ power.

  • same
  • less
  • more
Q.2

In a two stage reciprocating compressor with intercooler, the amount of work saved with incomplete intercooling is __________ that in case of complete intercooling.

  • less than
  • more than
Q.3

A compressor mostly used for supercharging of I.C. engines is

  • radial flow compressor
  • axial flow compressor
  • roots blower
  • reciprocating compressor
Q.4

The gas in cooling chamber of a closed cycle gas turbine is cooled at

  • constant volume
  • constant temperature
  • constant pressure
  • none of these
Q.5

Standard air is the air at __________ and relative humidity ofpercent.

  • 0.1 bar and 20° C
  • 1 bar and 20° C
  • 0.1 bar and 40° C
  • 1 bar and 40° C
Q.6

The volume of air delivered in a medium capacity air compressor per unit time is

  • 0.1 to 1.2 m3/s
  • 0.15 to 5 m3/s
  • above 5 m3/s
  • none of these
Q.7

In axial flow compressors, the flow of air is parallel to the axis of compressor.

  • Correct
  • Incorrect
Q.8

The overall isothermal efficiency of the compressor is defined as the ratio of

  • work required to compress the air isothermally to the actual work required to compress the air for the same pressure ratio
  • isothermal power to the shaft power or B.P. of the motor or engine required to drive the compressor
  • volume of free air delivery per stroke to the swept volume of the piston
  • isentropic power to the power required to drive the compressor
Q.9

The mean effective pressure of the compressor is the

  • actual volume of the air delivered by the compressor when reduced to normal temperature and pressure conditions
  • volume of air delivered by the compressor
  • volume of air sucked by the compressor during its suction stroke
  • none of the above
Q.10

The free air delivery is the volume of air that can be delivered by a compressor freely.

  • True
  • False
Q.11

The workdone on a compressor will be minimum if air is taken from

  • the atmosphere
  • a source at 0° C
  • a source of low temperature air
  • a source of high temperature air
Q.12

In a jet propulsion unit, the products of combustion after passing through the gas turbine are discharged into

  • atmosphere
  • vacuum
  • discharge nozzle
  • back to the compressor
Q.13

A 3 m3/min compressor means that it

  • compresses 3 m3/min of standard air
  • compresses 3 m3/ min of free air
  • delivers 3 m3/ min of compressed air
  • delivers 3 m3/ min of compressed air at delivery pressure
Q.14

In a single stage, single acting reciprocating air compressor without clearance volume, the workdone is maximum during

  • isothermal compression
  • isentropic compression
  • polytropic compression
  • none of these
Q.15

In a closed cycle gas turbine, the air is compressed

  • isothermally
  • polytropically
  • isentropically
  • none of these
Q.16

The ratio of the isothermal power to the shaft power or brake power of the motor or engine required to drive the compressor is called overall isothermal efficiency.

  • True
  • False
Q.17

The minimum work required for a three stage reciprocating air compressor is __________ the work required for each stage.

  • equal to
  • double
  • three times
  • six times
Q.18

The reason for volumetric efficiency of reciprocating compressor being less thanpercent is

  • pressure drop across the valves
  • superheating in compressor
  • clearance volume and leakages
  • all of these
Q.19

The ratio of the discharge pressure to the inlet pressure of air is called

  • compression ratio
  • expansion ratio
  • compressor efficiency
  • volumetric efficiency
Q.20

The compression ratio for the compressor is always __________ unity.

  • equal to
  • less than
  • more than
Q.21

The compressor capacity is defined as the

  • actual volume of the air delivered by the compressor when reduced to normal temperature and pressure conditions
  • volume of air delivered by the compressor
  • volume of air sucked by the compressor during its suction stroke
  • none of the above
Q.22

In a single stage, single acting reciprocating air compressor, without clearance volume, the workdone is minimum during

  • isothermal compression
  • isentropic compression
  • polytropic compression
  • none of these
Q.23

In a double acting compressor, the air is compressed

  • in one cylinder
  • in two cylinders
  • in a single cylinder on both sides of the piston
  • in two cylinders on both sides of the piston
Q.24

For a multi-stage compressor, the polytropic efficiency is constant throughout for all the stages.

  • True
  • False
Q.25

For minimum work in multi-stage compression, the workdone on all stages should be equal.

  • Yes
  • No
Q.26

A regenerator in a gas turbine improves thermal efficiency.

  • Correct
  • Incorrect
Q.27

The assumption made in two stage compression with intercooler is that

  • there is no pressure drop in the intercooler
  • the compression in both the cylinders is polytropic
  • the suction and delivery of air takes place at constant pressure
  • all of the above
Q.28

A simple turbo-jet engine is basically a gas turbine engine equipped with a propulsive nozzle and diffuser.

  • Agree
  • Disagree
Q.29

The basic principle of the rocket propulsion is the same as that of jet propulsion.

  • Yes
  • No
Q.30

In a high pressure compressor, the delivery pressure is

  • 1 to 5 bar
  • 5 to 8 bar
  • 8 to 10 bar
  • 10 to 15 bar
0 h : 0 m : 1 s